Ultrasonic diagnosis devices are widely used as devices capable of observing living organisms easily in real time together with X-ray computed tomography (CT) devices, magnetic resonance imaging (MRI) devices, and the like. Further, in recent years, their intended purpose has been expanded by utilization from conventional diagnostic imaging to treatment support such as puncture observation and contrast agent observation, and due to such a background, ultrasonic diagnosis devices are required to have a high image quality.
In the ultrasonic diagnosis devices, when there is a difference between a rising slew rate and a falling slew rate of a drive signal of an ultrasonic probe, a virtual image (artifact) occurs in a tomographic image or a blood flow image. For this reason, it is desirable that an adjustment can be performed so that the rising slew rate and the falling slew rate of the drive signal are equal to each other.
As an output circuit capable of adjusting the slew rate, Patent Document 1 discloses an electric waveform generating circuit which is capable of adjusting a slew rate, and includes a plurality of output circuits, an internal circuit that controls the output circuits, a replica gate having the same configuration as the output circuit, a slew rate adjustment pulse generation unit that controls an output timing of the replica gate, a switch unit that controls the slew rate of the replica gate, and an observation terminal that monitors an output signal of the replica gate, wherein an output waveform of the replica gate is monitored through the observation terminal, and the slew rate is adjusted to a desired slew rate through the switch unit.